EDIT: Yes I meant the loans stay with the estate which services the debtors. The house that is typically handed down to the next generation is now sold to make whole the debt.
Pennsylvania for example does have filial responsibility laws where under very specific circumstances debt incurred by the parents can be transferred to the children. One example is nursing home/end of life care, regardless of whether or not the child had any role in it.
Source: I live in PA. My elderly parents live in PA.
http://www.pacourts.us/assets/opinions/Superior/out/A36025_1...
This really doesn't have anything to do with inheritance, especially so since his mother wasn't (and presumably still isn't) deceased. It has to do with some states having laws requiring parents/children, who have the means to do so, to support their child/parent who is poor or otherwise incapable of supporting themselves.
In this court case, the child was found to be financially capable and also legally liable for supporting his mother. Because of this, he was found responsible for paying off the debt, but only as he was capable of doing so.
If the son in this case only made the national median income, had a large family to support, and didn't have any wiggle room in his budget, he very likely would not have been found liable for this debt.
That the parents are in a situation where they decide to sell their house to support their lifestyle is perhaps worth examining, but that's the problem, not that the contract they enter into has to be settled.